The horseshoe-shaped capital letter used to denote the ohm, the SI unit of electrical resistance — visually identical to, but formally distinct from, the Greek letter omega.
A vertical line entering the top of a broken circle — IEC 60417-5009, marking a control that puts equipment into a low-power state rather than fully disconnecting it.
A vertical line inside an unbroken circle — IEC 60417-5010, marking a button that switches equipment between fully on and fully off.
A vertical bar (|) — IEC 60417-5007, marking the control position that places equipment into a fully powered state.
A plain circle (◯) — IEC 60417-5008, marking the control position that disconnects power from the equipment.
A small square inside a larger square — IEC 60417-5172, marking equipment protected by double or reinforced insulation rather than an earth connection.
A circle enclosing a three-bar earth glyph — IEC 60417-5019, marking the protective earth (ground) terminal on Class I equipment.
A wavy line (∼) — IEC 60417-5032, indicating on a rating plate that equipment is suitable for alternating current.
A solid line above a dashed line — IEC 60417-5031, indicating on a rating plate that equipment is suitable for direct current.
A looped square with four outward corners, marking the Mac command key.
A hollow upward arrow, marking the shift key.
A right-pointing arrow meeting a vertical bar, marking the tab key.
An arrow turning down then left, marking the enter or return key.
An arrow leaving a circle, marking the escape key.
Three stacked horizontal lines that open a navigation menu.
Nested arcs radiating from a dot, indicating a wireless network signal.
An angular rune-like glyph marking a Bluetooth wireless connection.
A right-pointing triangle that starts playback.
Two upright bars that suspend playback.
A zigzag or a plain rectangle in a circuit, marking a resistor.
Two parallel lines across a break in a wire, marking a capacitor.
A row of humps or a filled rectangle in a wire, marking an inductor.
A triangle pointing at a bar, marking a diode.
A diode symbol with two arrows pointing away, marking a light-emitting diode.
A line with two angled leads inside a circle, one carrying an arrow.
The fifth Greek letter, conventionally a very small positive quantity.
Alternating long and short parallel lines, marking a cell or battery.
A break in a wire bridged by a hinged line, marking a switch.
A rectangle with a line through it, marking a fuse.
Two coils facing each other across parallel lines, marking a transformer.
A circle with a cross inside it, marking a lamp or indicator.
A circle containing the letter M, marking an electric motor.
The first Greek letter, used across science for angles, rates and particles.
The second Greek letter, used for beta particles, coefficients and angles.
The third Greek letter, used for gamma rays, functions and display response.
The fourth Greek letter, meaning change or difference in almost every field.
The eighth Greek letter, the default name for an angle.
The eleventh Greek letter, used for wavelength, eigenvalues and anonymous functions.
The twelfth Greek letter, and the SI prefix for one millionth.
The eighteenth Greek letter, used for standard deviation and stress.
The seventeenth Greek letter, used for density and resistivity.
The twenty-first Greek letter, used for the golden ratio and magnetic flux.
The last Greek letter, used for angular velocity — and the source of the ohm sign.
A lower-case m, the SI unit symbol for the metre.
The two-letter symbol kg, the SI unit symbol for the kilogram.
A lower-case s, the SI unit symbol for the second.
A capital A, the SI unit symbol for the ampere.
A capital K, the SI unit symbol for the kelvin.
The two letters cd, the SI unit symbol for the candela.
The two letters Hz, the SI unit symbol for the hertz.
A capital N, the SI unit symbol for the newton.
The two letters Pa, the SI unit symbol for the pascal.
A capital J, the SI unit symbol for the joule.
A capital W, the SI unit symbol for the watt.
A capital V, the SI unit symbol for the volt.
A capital F, the SI unit symbol for the farad.
A capital T, the SI unit symbol for the tesla.
The two letters lm, the SI unit symbol for the lumen.
The two letters lx, the SI unit symbol for the lux.
A degree sign followed by a capital C, marking a temperature in Celsius.
The two letters dB, marking a ratio on a logarithmic scale.
A small aeroplane silhouette, marking the setting that disables a device's radios.
A wave-like mark of curved strokes, indicating a near-field communication point.
A trident of three branches ending in a circle, a triangle and a square, marking a USB port.
A square block of black and white cells with three large squares at its corners.
One or two arrows curving into a near-closed circle, indicating reload or synchronisation.
A magnifying glass: a circle with a short diagonal handle.
Three dots joined by two lines, or a box with an arrow leaving it, marking a share action.
A downward arrow, usually above a horizontal bar or an open tray.
An upward arrow, usually above a horizontal bar or an open tray.
A rounded cloud outline, standing for a remote service or remote storage.
An upward triangle above a horizontal bar.
A rectangle with a small nub at one end, filled in proportion to the charge remaining.
A row of bars of increasing height, showing received signal strength.
A toothed wheel, marking a control that opens settings or preferences.
A flattened oval outline, marking a USB Type-C port.
A ladder of coloured arrows from green to red, grading a product's energy efficiency.
A star inside a stylised label outline, marking energy-efficient products.
A plug or lightning bolt with a car, marking a charging point.
A truncated cone shown in two views, stating which projection convention a drawing uses.
A truncated cone in two views, mirrored from the first-angle symbol, stating the American convention.
A long-dash-dot line marking an axis of symmetry or a circle's centre.
A line of short even dashes, showing an edge concealed behind material.
A circle with a diagonal stroke, marking a dimension as a diameter.
A capital R before a dimension, marking it as a radius.
A flat-bottomed bracket shape, calling for a flat-bottomed enlarged hole.
A shallow V shape, calling for a conical widening at a hole's mouth.
A check-mark-like tick with a long arm, carrying surface texture requirements.
An arrow and horizontal reference line carrying weld type, size and process.
A rectangular box divided into cells, stating a geometric characteristic and its tolerance.
A parallelogram, specifying how flat a surface must be.
An upright T on a base line, specifying squareness to a datum.
A boxed letter on a filled or open triangle, establishing a reference.
Two triangles meeting at their points, the generic valve on a flow diagram.
A ball or flap against a seat, permitting flow one way only.
A circle with a triangular wedge, marking a pump and its flow direction.
A circle on a stem with a pointer or letters, marking a pressure indicator.
A circle or rectangle crossed by a zigzag, marking heat transfer between streams.
A flat-backed D shape, outputting true only when every input is true.
A curved-back shield shape, outputting true when any input is true.
A coil beside a switch, showing a circuit that a second circuit operates.
A resistor with an arrow touching it, marking a variable division of voltage.
A small rectangle between two plates, marking a quartz frequency reference.